Proteolysis has emerged as a major fundamental mechanism of many biological processes ranging from development to apoptosis. Traditionally, studies of proteolytic enzymes have focused heavily on biochemical mechanisms, structure, and inhibition, and most meetings on proteolysis have reflected this interest. However, as new methods have emerged for the study of protease function in vivo, there are an increasing number of laboratories involved in studies of protease biology. The objective of the Third Meeting on the Biology of Proteolysis is to bring together investigators of protease biology with those who study the biochemical and structural properties of these enzymes. Clearly, given the similarities between proteolytic systems involved in distinct biological processes, this meeting presents an exciting opportunity for participants to learn about recent developments that will be relevant to their own research. The program will include eight sessions covering the most prominent biological systems involving proteolysis, which will be led by two outstanding and well-known investigators in these areas. With the exception of overview talks presented by the session chairs, all of the talks and posters to be presented will be selected from submitted abstracts, and most of the talks will be given by students, postdoctoral fellows and other younger investigators. It is expected that more than 250 scientists will attend. Of these, over half are likely to be graduate students and postdoctoral fellows. The subsequent meetings (2003 and 2005) will follow a similar format which will include topics that are highly relevant to the current research at the time of the meeting.